1. Field of the Invention
The present general inventive concept relates to a method of adjusting a displaying state of a display apparatus, and more particularly, to a method of adjusting a displaying state of a display apparatus, in which a color sensation is varied to have directionality and linearity between gradations of a gray level, thereby improving color representation of the display apparatus.
2. Description of the Related Art
Recently, display apparatuses, such as a monitor for a personal computer, a television, and the like, have been required to be lightweight and thin. To satisfy these requirements, a liquid crystal display (LCD) module has been widely used instead of a conventional cathode ray tube (CRT) as the display apparatus.
In the LCD module, a liquid crystal having anisotropic permittivity is filled between two substrates, and the liquid crystal becomes opaque or transparent according to the intensity of an electric field applied thereto, thereby displaying a picture.
The LCD module cannot display a real color because of displaying characteristics of the LCD module. For example, white displayed on the LCD module inclines toward red even though a video signal of a white level is processed. Further, the more a signal approaches a black level, the more color inclines toward blue.
There are various standards for color representation of the display apparatus. For example, The Swedish Confederation of Professional Employees (TCO) 03 standard requires that a color temperature variation (Δu′v′) at a gradation of a gray level of 105 or more be smaller than 0.02 to make the display apparatus have a high color maintenance regardless of a variation of brightness.
With respect to the TCO 03 standard, a conventional display apparatus has the following problems.
The conventional display apparatus has a color temperature distribution ranging from 7,200K to 11,500K with regard to all gradations, so that the color temperature is widely varied according to the gradation. Actually, the more the color deviates from a white level and approaches a black level, the more the color inclines toward blue or a dark color sensation. Thus, even though a picture contains a real color, the color is distorted, thereby deteriorating the color representation.
Further, in the conventional display apparatus comprising the LCD module, the Δu′v′ is not smaller than 0.02 at the gradation of 105 or more, and is insufficient to satisfy the TCO 03 standard. FIG. 1 is a graph illustrating data measured with respect to a picture of a gray level in the LCD module of the conventional display apparatus. That is, FIG. 1 shows the Δu′v′ measured with respect to a gray level of 16 gradations. As shown in FIG. 1, the Δu′v′ is not smaller than 0.02 at the gradation of 105 or more.
To satisfy the TCO 03 standard, the conventional display apparatus divides the gray level into a high and a low, thereby adjusting a red, green, blue (RGB) gain value and an offset value. As another method, a predetermined color value is subtracted from or added to an RGB gamma value, so that the Δu′v′ is adjusted to be smaller than 0.02.
FIG. 2 is a graph illustrating the data measured after adjusting the RGB gamma value. Referring to FIG. 2, the RGB gamma value of the conventional display apparatus is adjusted, thereby adjusting the Δu′v′ to be smaller than 0.02 at all of the gradations. However, according to displaying characteristics of FIG. 2, coordinate values of each gradation are dispersively distributed without directionality, so that color sensation is distorted and variegated when a picture is displayed on the LCD module.
Further, in the conventional display apparatus, the Δu′v′ is made smaller than 0.02 at all of the gradations by adjusting the RGB gamma value, but the Δu′v′ is different according to the gradations. Here, the Δu′v′ affects the color sensation at each gradation, so that a linearity of all of the gradations is deteriorated when the Δu′v′ is different between the gradations.